Multiple fuse plug



' INVENTOR Jred W WILZEL'LZJVQS BY Q6 A'ITORNEYS F. w. WILLIAMS MULTIPLE FUSE PLUG Flled Jan 9 1926 Oct y WITNESSES /)7 W %j I Patented Oct. 11, 1927.

UNITED STATES;

FRED W. WILLIAMS, OF SANTA MARIA, CALIFORNIA.

MULTIPLE ruse PLUG.

application filed J anu'ary This invention rel-ates to improvements in fuse plugs; and it consists of the constructions, combinations and arrangements here in described and claimed.

An object of the invention is -to provide a fuse plug having a plurality of fuses which can be successively introducedinto the elec'- trical circuit as preceding ones are melted or burned-out, thereby obviating the necessity of making a replacement with an entirely new plug each time a fuse Wire is burned, a further purpose of the invention being to construct the plug with such simplicity that it canbe I manufactured very cheaply. g

' Other objects and advantages appear in the following specification, reference-being had to the .accompanyingdrawing, in'which Figure 1 is a central' longitudinal section of a fuse plug constructed in accordance-with the invention.

Figure 2 is a detail cross section taken substantially on the line 2-2 of Figure 1. Figure 3 isa plan view of the plug.

Figure-4 is an inverted perspective view of the revoluble insulating disk.

Figure 5 is a cross section taken on the'line 5'5 of Figure 1.

In carrying out the invention proyision IS made of a porcelain or other insulatmg base 1 to the small end of which the customary metallic shell 2 is suitably aflixed. This shell is stamped into the shape of screw threads so that the plugs can be screwed into a complementary receptacle in the fuse box.

The shell 2 has. electrical connection with the side contact 3. This contact terminates in a head 4 and a tortuously bent end 5 which functions as a spring.

The center contact 6 is appropriately fixed in the base 1, and extends a short distance above the surface of the larger end of the base. An insulating disk 7 of rubber, fiber or other suitable material. has a central hole 8 which receives the head 9 of the center con- 1) tact and permits engagement of said head with the center of the fusible element or spider 10.

The insulating disk 7 is revoluble in respect to the base 1, and for this purpose provision is made of a brass or other metallic cap 11 which at 12 is bent over the edge of the mica disk 13, holding the disk in place '7 is depressed at 17 in the formation theredepression.

9, 1926. Serial No. 80,257.

upon the insulating disk 7 and alt-14 is bent under the edge of the base 1 in order to retain the cap. However, the cap is sufiiciently loose at '14 to permit manual rev0lu tioii'o'r turning of the insulating disk and its carried parts in reference to the base 1, side contact 3 and center contact 6. The brass cap 11 is also criinped at 15 (Figs. 3 and 5) to tightly hold the cap in place at the edge of the disk.

Particular reference is made to the fusible element 10. This element resembles the hub and spokes of awheel.' The arms 16 thereof radiate from the common-center which 'makes engagement with the head 9 of the center contact 6. The insulating disk of, providing a'recess or pocket at the bottom of which the element10 is firmly lodged. The. shape of the depression 17 will agree exactly with the shape of the element 10, and by lookingdown upon the multiple fuse plug and through the mica window 13 (Fig. 3) the observer sees the depression 17 and the fusible element 10 at the bottom of the The arms 16 of the fusible element are reduced or constricted at 18 but immediately broadened at 19 to produce what might be called heads. These heads have a definite purpose' The constriction 18 may be varied to suit the amperage of the fuse plug. In other words, a fuse plug designed to carry six amperes of current will be narrower at the constriction 18 than one designed t carry ten amperes.

As to the purpose of the heads 19': The insulating disk 7 has non-circular openings 20 (Figs. 4 and 5) at the outer extremities of the depressions l7. Thehead 4 of the side contact 3 occupies these openings in succession, as the cap 11 is turned to introduce new fuse arms into the circuit. One of the radial edges of each opening is beveled'at 21 roviding an approach over WhlCh the contact head 4 can readily move when the cap 11 is turned to displace the head 4 from the respective openings 20. Presuming a particular fuse arm 16 to be mounted at the constriction 18. It is apparent that there would be some possibility of the free or broken end dropping down into the respective opening 10 20 to conflict with and probably impair the freedom of action of the spring and the rotation of the cap 11. However, the heads 19 are broader than the openings and thereby rest on each side of the openings, preventing the foregoing contingency.

A pointer or indicator 22 marks the position of the contactorvhead 4. -This pointer registers with the head 4 in the radial direction, and by observing the indicator 22 the user of the plug can ascertain the position of' the contactor head and turn the cap 11 accordingly. 1

The operation of the fuse plug is readily understood. The reader will remember that the insulating disk 7 has a depression 17 of the shape of the fusible element 10. This element is shaped like the spokes and hub of a wheel, and the depression 17 agrees therewith. The' fusible element is firmly lodged at the bottom of the'depression, and it is visible from the top of the fuse plug.

The head 4; ofthe side contact 3 enters the openings 20 from beneath, and makes contact with the fusible element on the underside of the heads 19. The engagement of, the head 4 with the heads 19 is successive, and occurs each time that the cap 11 is 'turned sufiicientlyfar in the right direction.-

The tortuously bent end 5 of the side contact imparts the necessary resiliency to the head 4, causing the latter to snap into the successive opening and make good contact with the exposed endof the fusible element.

The engagement of the head 9 of the cen-' ter contact 6 and of the head 4 with the underside of the fusible element furnish the support of the insulating disk 7 in spaced relationship with the large end of the base 1. The head 9 of the center contact 'furnishes a bearing upon which the-cap 11 is turned. The electrical circuit is completed from the threaded shell 2 to the center contact 6 to the side contact 3 and that one of the arms 16 of the fusible element 10 that happens to be in registering position.

Upon melting of that arm at the constriction 18 the electrical circuit will of course be opened, but the user can turn the cap 11 until the next arm is. brought into operation. The fragment of the former arm wi however, not drop through the respective opening 20 because it is made sufficiently broad to overlap the edges of the opening (see Figs. 2 and 5) and will therefore retain itsposition.

While the construction and arrangement of the improved multiple plug is that of a generally preferred form, obviously modifications and changes may be made without departing from the spirit of the invention or the scope of the claims.

I claim L'A fuse plug comprisin and side contacts carried l) a base, center y the base, a

fusible element having a plurality of radial arms, an insulating disk having a depression on top corresponding with the shape of the I I fusible element at the bottom of which depression the fusible element is firmly lodged, said disk having a central opening at which the center contact makes engagement with the element in the center, a plurality ofbpen ings at which the substantial extremities of the arms are exposed at the underside and at which theside contact makes engagement therewith; a transparent pane through which the entire depression and element are visible, and-means both clamping the pane upon the insulating disk and providing-arotatable vmounting for the disk upon the base permitting turningof the disk to cause successive engagement of the 'side contact with the respective arms, and indicator means stationarily mounted upon the base coinciding in radial position with the side contact. I

2. A fuse plug comprising a base, center and side contacts -carried by the base, a fusible element having a plurality of radial arms, an insulating support for said element having openings exposing the element on the underside respectively for permanent engagement of the center contact and for successive engagement of the side contact with each of the arms, and a bent formatlon incorporated in the end of the side contact increasing its resiliency so that it functions as a spring.

3. A- fuse plug comprising a base, center and side contacts carried by the base, a fusible element having a plurality of radial arms, an insulating support for'said element havingopenings exposing the element on the underside respectively for permanent engagement of the center contact and for successive engagement of the side contact with each of the arms, a bent'formation incorporated in the end of the side contact ll increasing its resiliency so that it functions as a spring, means rotatably mounting the insulating support upon the base, and bevels cut at one of the radial edges of eachof the arm openings permitting depression of the spring end of the sidecontact and disengagement thereof from the respective opening when turning said support for engagement of the spring end with the next arm.

-FRED W. WILLIAMS. 

